"Flying in the face of traditional laws of physics, the EmDrive makes use of a magnetron and microwaves to create a propellant-less propulsion system. By pushing microwaves into a closed, truncated cone and back towards the small end of said cone, the drive creates the momentum and force necessary to propel a craft forward. Because the system is a reaction-less drive, it goes against humankind’s fundamental comprehension of physics, hence its controversial nature."